/*++

    Copyright (c) Microsoft Corporation. All rights reserved.

Module Name:

    TestsUtility.c

Abstract:

    General utility functions that are specific to Tests library.
    This is not a Module. It is a set of functions that are called without using DMFMODULE.

Environment:

    Kernel-mode Driver Framework

--*/

#define _CRT_RAND_S

// DMF specific definitions.
//
#include "DmfModules.Library.Tests.h"
#include "DmfModules.Library.Tests.Trace.h"

#if defined(DMF_INCLUDE_TMH)
#include "TestsUtility.tmh"
#endif

///////////////////////////////////////////////////////////////////////////////////////////////////////
// Module Private Enumerations and Structures
///////////////////////////////////////////////////////////////////////////////////////////////////////
//

// Memory Pool Tag.
//
#define MemoryTag 'ltUT'

///////////////////////////////////////////////////////////////////////////////////////////////////////
// Support Code
///////////////////////////////////////////////////////////////////////////////////////////////////////
//


///////////////////////////////////////////////////////////////////////////////////////////////////////
// Public Calls by Client
///////////////////////////////////////////////////////////////////////////////////////////////////////
//

_Must_inspect_result_
_IRQL_requires_same_
ULONG
TestsUtility_GenerateRandomNumber(
    _In_ ULONG Minimum,
    _In_ ULONG Maximum
    )
/*++

Routine Description:

    This function generates a random number withing a specified range.

Arguments:

    Minimum - Minimal number of the range.
    Maximum - Maximum number of the range 

Return Value:

    The generated random number.

    --*/
{
    ULONG random;
    ULONGLONG range;

    DmfAssert(Maximum >= Minimum);

    range = Maximum - Minimum;
    range += 1;

#if !defined(DMF_USER_MODE)
    ULONG seed;

    seed = (ULONG)ReadTimeStampCounter();
    random = Minimum + RtlRandomEx(&seed) % range;
#else
    unsigned int randomNumber;

    if (rand_s(&randomNumber) == 0)
    {
        random = Minimum + randomNumber % range;
    }
    else
    {
        DmfAssert(FALSE);
        random = 0;
    }
#endif

    return random;
}

_IRQL_requires_same_
VOID
TestsUtility_FillWithSequentialData(
    _Out_writes_(Size) UINT8* Buffer,
    _In_ ULONG Size
    )
/*++

Routine Description:

    This function populates the buffer with sequential 
    data, that starts from a random number.

Arguments:

    Buffer - Buffer to populate.
    Size - Buffer size. 

Return Value:

    None.

    --*/
{
    UINT8 currentValue;
    ULONG index;

    currentValue = (UINT8)TestsUtility_GenerateRandomNumber(0,
                                                            BYTE_MAX);
    
    for (index = 0; index < Size; ++ index)
    {
        // Ignore integer overflow, just restart from zero.
        //
        Buffer[index] = currentValue;
        ++ currentValue;
    }
}

#pragma code_seg("PAGE")
_IRQL_requires_same_
_IRQL_requires_max_(APC_LEVEL)
VOID
TestsUtility_YieldExecution()
/*++

Routine Description:

    This function forces scheduler to yield execution to another thread.

Arguments:

    None.

Return Value:

    None.

    --*/

{
    PAGED_CODE();

#if !defined(DMF_USER_MODE)
    LARGE_INTEGER delayInterval;

    delayInterval.QuadPart = -1;

    KeDelayExecutionThread(KernelMode,
                           TRUE,
                           &delayInterval);
#else
    Sleep(0);
#endif
}
#pragma code_seg()

#define CRC_INITIAL_VALUE 0xFFFFU
#define CRC(crcval, data)   ((UINT16)((crcval) << 8) ^ CRCTable[(((crcval) >> 8) ^ ((UINT16)(data) & 0xFFU))])

static 
const 
UINT16 
CRCTable[256] =
{
    0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, 0x8108,
    0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, 0x1231, 0x0210,
    0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, 0x9339, 0x8318, 0xb37b,
    0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, 0x2462, 0x3443, 0x0420, 0x1401,
    0x64e6, 0x74c7, 0x44a4, 0x5485, 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee,
    0xf5cf, 0xc5ac, 0xd58d, 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6,
    0x5695, 0x46b4, 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d,
    0xc7bc, 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
    0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, 0x5af5,
    0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, 0xdbfd, 0xcbdc,
    0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, 0x6ca6, 0x7c87, 0x4ce4,
    0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, 0xedae, 0xfd8f, 0xcdec, 0xddcd,
    0xad2a, 0xbd0b, 0x8d68, 0x9d49, 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13,
    0x2e32, 0x1e51, 0x0e70, 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a,
    0x9f59, 0x8f78, 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e,
    0xe16f, 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
    0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, 0x02b1,
    0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, 0xb5ea, 0xa5cb,
    0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, 0x34e2, 0x24c3, 0x14a0,
    0x0481, 0x7466, 0x6447, 0x5424, 0x4405, 0xa7db, 0xb7fa, 0x8799, 0x97b8,
    0xe75f, 0xf77e, 0xc71d, 0xd73c, 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657,
    0x7676, 0x4615, 0x5634, 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9,
    0xb98a, 0xa9ab, 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882,
    0x28a3, 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
    0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, 0xfd2e,
    0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, 0x7c26, 0x6c07,
    0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, 0xef1f, 0xff3e, 0xcf5d,
    0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, 0x6e17, 0x7e36, 0x4e55, 0x5e74,
    0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
};

_Must_inspect_result_
_IRQL_requires_same_
UINT16
TestsUtility_CrcCompute(
    _In_ UINT8* Message,
    _In_ UINT32 NumberOfBytes
    )
/*++

Routine Description:

    This function computes the 16-bit CRC of the given message and
    returns it.

Arguments:

    Message - Pointer to the given message.
    NumberOfBytes - Number of bytes to compute the CRC over.

Return Value:

    16-bit CRC corresponding to the given message.

--*/
{
    UINT32 index;
    UINT16 accumulatedValue;

    accumulatedValue = CRC_INITIAL_VALUE;
    for (index = 0U; index < NumberOfBytes; index++)
    {
        accumulatedValue = CRC(accumulatedValue,
                               Message[index]);
    }

    return accumulatedValue;
}

// eof: TestsUtility.c
//
